Production calculator



Nov. 28, 1933. H. KA FFINE 1,937,277

PRODUCTION CALCULATOR Filed Nov. 24, 1931 ESTIMATE FEEDS a snqx s FOR M |LL|NG Plffl-IINES PART TOOL OPERAT N MATERIAL OF PART REVOLUTI 0N5 PER M\NUTE TABLE OF CUTTING SPEEDS 8O HO I20 I30 I40 I60 I80 200 i 16 J FEED g! FOR SAWING OPEFAITIoNS 6 usE cum HALF u esrmmw FEi-D- 1 Y/ 7Q I A 2 ,ZFn/enior,

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Patented Nov. 28, 1933 PATENT OFFICE PRODUCTION CALCULATOR Heinrich Kaffine, West Reading, Pa.

Application November 24, 1931 Serial No. 576,975

4 Claims.

, The object of the invention is to provide broadly a production calculator, but more particularly one which is so designed as to calculate or estimate both the rate of feed and the speed of the tool j employed for a given operation in a milling machine.

It is well known by practicalmechanics, by production managers of machine shops, and by too] designers that various factors enter into the op- 19 eration of a tool in any form of cutting machine.

In now considering a milling machine, the important factors comprise the relative strength of the article to be milled, the relative strength of the tool, the particular kind of operation involved, the width and depth of the cut, the mateas cutting tool, that is, the co-relation between the diameter of the cutting tool and its revolutions per minute. Therefore, an object is to provide a calculator having relatively movable parts bearing numerical factors, so arranged that by shift-= 7 ing said parts as hereinafter described the information sought can be read directly therefrom.

With these and other objects in mind, the present invention comprises further details of construction and operation which are fully brought ,35 out in the following description when read in conjunction with the accompanying drawing, in which Fig. 1 is a plan view of the obverse of a device comprising one embodiment of the invention; Fig. 2 is a similar view of the reverse of the same; Fig. 3 is a plan view of the graduated slide per se (horizontally arranged) and Fig. 4 is a transverse section on the line 44 of Fig. 1.

Referring to the drawing, a member comprising a card of stiff paper board or a plate of preferably 5 light-weight material 1 is provided with a longitudinally extending channel 2 of either less than, or throughout, the entire length of said member, and through which a slide 3 is adapted to reciprocate. Said member adjacent to one end of said channel may be cut away at 4, if desired, to make it easy to manually engage said slide when it is in its innermost position. Also, said member is provided upon its obverse face with apertures or windows 5, 6, '7, 8 and 9, which in each instance can ' extend through the wall of and into said channel,

so that indicia carried by said slide can be readily seen therethrough.

Referring now to the obverse surface of the calculator, upon one side of the first aperture 5 are two tables 10 and 11, side by side and containing in the former table in vertical arrangement several terms, which are descriptive of the article to be milled, namely, Fragile, Medium and Strong, while in the latter table are several terms, which are descriptive of the holding or clamping Tool to be employed in the operation, namely, Light, Medium and Strong. Upon the opposite side of the aperture 5 'is a table in which are listed in vertical arrangement the several types of operations for which the milling ma- (0 chine is adapted, including Sawing, Vertical slotting, Vertical milling, slotting, Surface milling, Side milling and possibly others.

Below the first aperture 5 is the second aperture 6, to one side of which are tables 13 and 14 in which are listed, respectively, the width and depth of the cut to be made, while upon the opposite side of said second aperture is a table 15 in which are, listed also in vertical arrangement the various metals of which the article to be milled may be composed, namely, Tool steel Drill rod Cold drawn steel Screw steel, Cast iron, Machine steel, Cold rolled steel Brass and Aluminum Below the aperture 6 is the third aperture 7, to one side of which are two tables in which are listed, respectively, the Horsepower'of the machine and the Diameter of the cutter Still below said last-named aperture is the fourth aperture 8 through which one of the composite factors is viewed as hereinafter described, while to the side of said last-named apertures '7 and 8 is the fifth and final aperture 9, to one side of which is a table 18 in which are vertically arranged the several types of metal also listed in table 15, but in this instance for indicating the Cutting speed required for the particular metal (or other material being handled).

Referring now to the slide 3, its surface is provided with two normally vertical rows 19 and 20 of figures, which are adapted to be shifted step by step and viewed and read in the first instance through the apertures 5, 6, '7 and 8 in sequence, and in the second instance through the aperture 9. The reverse of the plate member 1 is in turn provided with a Table of cutting speeds, comprisinghorizcntal lines 21, opposite figures denoting the Diameter in inches of the milling tool and vertical columns 22 corresponding with the Feet per minute of the cutting speed. 7.10

Within the spaces in which said lines and columns intersect there are numerals to denote the Revolutions per minute at which the cutting tool is to be rotated.

The operation of the calculator is as follows:-- Assuming that the part to be milled is of "Fragile construction, reading to the right we find .582 The slide 3 is then pulled down until .582 is even with or abreast of the last line 10' of the first table 10. If the supporting or positioning tool or clamp is of but medium strength, we find now opposite the word Medium the figure .438 which in turn is brought down (by further moving the slide 3) until said figure is opposite the last line 11 of said. second table. If the work to be done is a surface milling operation, the figure .364 now opposite the term Surface milling in table 12 is brought down (by further moving the slide 3) until said last-named figure is opposite the last line 12 in the Operation table.

If the width of the desired cut is under ii", the figure 2.175 now opposite that line in table 13 is brought down to the last line 13 in said table. If the depth of the cut is {%"-1 the'figure 1.125 now opposite that indication in table 14' is brought down until it is opposite the last line 14 in that table. If the material is of cast iron; the figure .640 is brought into alignment with the last line 15' in the table 15 of materials. If the horsepower of the machine is 1-3 the figure 1.492 now opposite that power indication is brought down to the last line 16 in the table 16, and if the diameter of the cutter is 1-2 inches, the figure 1.358 is lowered into alignment with the last line 1'7 of the table 1'7.

The necessary, or at least the advisable, rate of feed of the movable bed of the milling machine, having been automatically brought into unobstructed view, can now be read through the "Feed aperture 8, and in this case will be seen to be 1.802 feet per minute, .so that the feed of the machine may be readily set in the usual manner' at the point or rate nearest to that figure which the construction of the particular machine permits. For the revolutions per minute at which the tool should be run, we first look through the aperture 9 and opposite the designation "Cast iron find the figure 86.6, the cornot cutting speed in feet per minute of the cutter. Turning the calculator over, we'find'upon the reverse side in the uppermost horizontal column that is the figure nearest to the 86.6. In the farthest left hand (or farthest right hand) vertical column we look for the diameter of the cutting tool being used, which in this instance may be 1%". Reading horizontally across from thisfigure, and vertically below the 90, we find 183" which is substantially the exact number of revolutions per minute at which the tool in this case should theoretically be run. (All of the figures of this table are not filled in.) Obviously, if there is no means upon the particular machine for setting the speed at the exact figure designated by the table, the speed should be set as near as possible to that figure.

In making use of the improved calculator, it should be borne in mind that it is primarily intended for use with milling work with high-speed steel cutters, and when the average fairly clean finished surface is desired after only a single cut, as is usually the case in mass production. In case carbon steel cutters are being used, only onehalf the estimated feed and speed should be used.

At times it is also advisable to make two cuts, in order to leave a much smoother finished surface than is usually possible with but a single cut, or whenever greater accuracy is demanded. In such cases one makes a roughing cut to remove the bulk of the material, and leaves only sufficient material to provide for a relatively thin finishing out. It is general practice to use for roughing cuts a fast feed with a comparatively slow speed, and for finishing cuts a slow feed with a comparatively high speed in order to acquire the desired smoothness of surface.

Upon the calculator might appear such a statement as:-This calculator applies for jobs with high-speed steel cutters and average finish in one cut. Where two cuts are necessary, use twice the estimated feed for the roughing cut, and halve the estimated feed for finishing out. For Sawing operations always use one-half of the estimated feed. Let us first consider the use of the calcu latorforthe average-one-cut job. =With a given feed-'therealways goes a given speed for each kind or material, and if the feedincreasesthe speed also increases. Considering now the roughing cut in a two-cut operation, we use twice the estimated feed, but do not increase the speed of the cutting tool, thus insuring a high'i'eed with a eompartively low speed asintended. Considering nowthe finishing cut in a two-cut operation, we use one-half of the indicated feed with the directly indicated speed, thus insuring a low teed with a comparatively high speed asindicated.

Obviously, the number, kind, arrangement and substance of the tables used may be revised in order to adapt the calculator to'perticular needs 01 various machines, operations, materials, special tools, etc. The feature of primary importance is the provision of a movable element with indicia, which when said element is progressively shifted in accordance with co-related tablesim dicates a result which in effect is the composite of selected portions of those tables.

Having thus described my invention-what I claim and desire to protect by Letters Patent of the United States is:-

1. A calculator, comprising an element having a longitudinally extending channel and aperture. opening laterally into said channel, and a second element slidably mounted within said channel,

tables carried by said first element adjacent to l5 a plurality of said apertures, and indicia carried. by said second element and visible through said apertures in relation to said tables, said second element being movable step-by-step in accordance with selective items of said tables in sequence, and a portion of said indicia being finally visible through one of said apertures and representing a composite of the items selected from said tables.

2. A calculator for the proper setting of machinery, comprising an element carrying tables of the controlling factors for such machine setting and each table having a plurality of items, and a second element carrying indicia and movable in accordance with the selected items of each of said tables in sequence, whereby the final position of said second element with respect to said first element indicates a portion of said indicia' which represents the composite of the respective items selected from said tables.

3. A calculator for the proper setting of the feed of a milling machine, comprising an element having tables representing the relative strength of the article to be milled, the relative strength of the clamping device, the operation to be performed, the width and depth of the cut, the material of the article, the power of the machine and the diameter of the cutter, and a second element slidable with respect to the first and carrying indicia which with respect to the items of said tables permits said second element to be moved step-by-step, until that portion of said indicia in final position with relation to a given portion of said first element represents the composite of the selected items of said tables, that is, the rate of feed for the machine.

4. A calculator for the proper setting of the feed of a milling machine, comprising an element having tables representing the relative strength of the article to be milled, the relative strength of the clamping device, the operation to be performed, the width and depth of the cut, the material of the article, the power of the machine and the diameter of the cutter, a second element slidable with respect to the first and carrying indicia which with respect to the items of said tables permits said second element to be moved step-by-step, until that portion of said indicia in final position with relation to a given portion of said first element represents the composite of the selected items of said tables, that is, the rate of feed for the machine, and a separate table carried by said first element listing the materials of which the article to be milled may be composed, and a separate set of indicia carried by said second element and comparable with said last-named table, whereby that portion of said last-mentioned indicia opposite the name of the material of the particular article when said second element is in its final position indicates the cutting speed of the cutting tool for that article.

HEINRICH KAFFINE. 

